The present invention relates to a surgical mesh and, more particularly, to a soft and pliable multifilament surgical support mesh exhibiting improved resistance to inhabitation of bacteria and other infectious matter.
Using surgical mesh for the repair and restoration of living tissue is well known. For example, surgical mesh may be used to support and/or reinforce a damaged or weakened portion of the body. In this regard the mesh must additionally be sufficiently porous to allow for growth of tissue through the graft after implantation. The healing tissue grows through porous openings in the implanted mesh, thereby assimilating the mesh and adding structural integrity to the tissue.
Surgical mesh may be produced by knitting, weaving, braiding, or otherwise forming a plurality of yarns into a support trellis. Moreover, such mesh may be produced with monofilament or multifilament yarns made of materials such as polypropylene and polyester. Surgical mesh formed of monofilament yarn provides satisfactory reinforcement ability, but is generally stiff and has limited pliability. In contrast, surgical mesh formed of multifilament yarn is soft and pliable in comparison to mesh formed of monofilament yarn.
However, mesh formed of multifilament yarn may tend to harbor infectious matter such as bacteria. Particularly, the small void areas or interstitial spaces between the filaments of a multifilament yarn may promote the breeding of such bacteria. To date, surgeons typically prefer the monofilament design because of its improved resistance to harboring of infectious matter. As a result of this choice, surgeons must forego the advantages associated with multifilament yarns.
An example of a prior art surgical mesh is disclosed in U.S. Pat. No. 2,671,444. The surgical mesh described therein is an integral network of interconnecting yarns formed by molding a polyethylene resin. In essence, the ""444 mesh is a molded, monofilament mesh and, hence, is relatively stiff and exhibits limited pliability.
U.S. Pat. No. 3,054,406 discloses another example of a surgical mesh used for repair and restoration of living tissue. The surgical mesh described therein may be woven from either monofilament or multifilament polyethylene yarns. The mesh has limited pliability when formed of monofilament yarns, and may be prone to harboring of infectious matter when formed of multifilament yarns.
U.S. Pat. No. 4,452,245 discloses still another example of a surgical mesh. The surgical mesh described therein is formed with monofilament polypropylene yarns which are knitted into a continuous tubular shape. The knitted mesh is porous and exhibits infection-resistant characteristics because of its monofilament construction. However, the monofilament mesh tends to be stiff and relatively non-pliable, which detracts from the body""s ability to incorporate the mesh.
Surgical support mesh has been extremely useful in the field of repairing soft tissue such as during a hernia repair operation. Groin herniorrhaphy is among the oldest and most common surgical procedures performed. Unfortunately, the average operative result is beset by a period of discomfort with resultant disability. Techniques have been developed, such as laparoscopic herniorrhaphy, with the intent to reduce morbidity and recurrence rates. Most trials, however, have noted only a moderate improvement in the pain and disability associated with the procedure. Further, the added cost of equipment, the need for general anesthesia, and the additional operating room time required for laparoscopic herniorrhaphy indicates that this procedure is less than ideal. There continues to be a need for a procedure that can effectively address all the considerations of cost, disability, and hernia recurrence for patients with an inguinal hernia
While the placement of a prosthetic mesh in the properitoneal space is currently performed with either a laparoscopic or an open technique, it is desirable to perform the procedure through even less invasive means. One such means contemplated involves the use of needles to deliver the mesh into the peritoneal cavity. Delivery of mesh by means of a needle, however, has heretofore not been possible in part due to the unavailability of mesh which is thin enough to be passed through the cannula of a needle, yet of sufficient strength and flexibility to adequately serve its intended purpose.
There is therefore a need for a soft tissue surgical mesh which can be made having a thickness that allows the mesh to be rolled or folded and thereafter inserted into the cannula of a needle for deployment in the body and which exhibits both the soft and pliable characteristics of a mesh produced from multifilament yarns and the infection resistance of a mesh produced from monofilament yarns. The mesh should also be non-linting, fray resistant, and ravel resistant.
The present invention, which addresses the needs of the art, provides a soft and pliable surgical mesh. The mesh includes a support trellis formed of multifilament yarns encapsulated within an infection-impervious matrix whereby the interstitial voids located between the filaments of the yarns are enclosed within the matrix. The matrix also imparts a requisite degree of ravel resistance to the mesh wherein the yarns will be prevented from shifting or separating. The mesh may be composed of fine multifilament yarns in a knitted or woven construction that would possess the desired mechanical strength and porosity for use in tissue repair or reinforcement.
The present invention also provides a method of producing a soft and pliable surgical mesh exhibiting increased resistance to inhabitation of infectious matter from a support trellis formed of multifilament yarns. The method includes the step of encapsulating the multifilament yarns within an infection-impervious matrix whereby the interstitial voids located between the filaments of the yarns are enclosed within the matrix. In one embodiment the fabric is made very thin to facilitate delivery through a minimally invasive device. The thickness of the fabric is tailored to the specific application and delivery apparatus. Such techniques as pressing or calendaring of the yarns in the finishing-off operation using heat and/or pressure to compress the fabric to the desired thickness may also be employed.
The present invention provides a mesh fabric that is designed to be particularly useful in minimally invasive surgical procedures for repairing and/or reinforcing tissue, such as during hernia repair. Due to its thin profile, the mesh fabric may be rolled or folded to occupy a sufficiently small volume to facilitate its introduction and delivery into the body using such devices as trocars, cannulas and the like. The mesh may also have an elastic memory imparted thereto so as to return to the desired configuration once removed from the delivery device. For example, the mesh may be designed to unfurl and assume a relatively planar configuration once deployed from the delivery device.
The present invention also provides a method of repairing a damaged portion of a patient""s body. The method includes the step of providing a soft surgical mesh. In some applications the mesh may further be rolled, folded, or otherwise compressed in size to fit within the cannula of a laparoscopic delivery device. The mesh of the present invention includes a support trellis formed of multifilament yarns encapsulated within an infection-impervious matrix whereby the mesh is soft and pliable while simultaneously exhibiting a resistance to inhabitation of infectious matter. The method includes the further steps of accessing the damaged portion of the body, implanting the surgical mesh in the body to reinforce the damaged portion, and allowing the mesh to assimilate into the body.
As a result, the present invention provides a surgical support mesh which exhibits both the soft and pliable characteristics of a mesh produced from multifilament yarns and the infection resistance of a mesh produced from monofilament yarns. Moreover, the present invention provides a surgical support mesh which is non-linting, fray resistant, and ravel resistant. Further still, the mesh of the present invention may be formed with an appropriate thickness so as to be delivered into a peritoneal cavity via a laparoscopic device.